Optical element module, and apparatus and method for fixing optical element

ABSTRACT

A semiconductor laser ( 41 ) is fixed onto a base part ( 22 ) with a submount ( 32 ) and a reference optical axis ( 5 ) is determined by the semiconductor laser ( 41 ). A groove ( 222 ) having a U-shaped section is formed on a bonding part ( 221 ), and solder ( 31 ) is applied in the groove ( 222 ) and melted and a collimator lens ( 42 ) supported by a supporting arm ( 61 ) is moved to the groove ( 222 ). A light beam emitted from the semiconductor laser ( 41 ) is guided through the collimator lens ( 42 ) to an image pickup part ( 7 ), where an image representing the state of the light beam is acquired. The collimator lens ( 42 ) is positioned with respect to the reference optical axis ( 5 ) on the basis of the image and fixed onto the base part ( 22 ) out of contact therewith, with the solder interposed therebetween. This simplifies a structure of an optical element module ( 11 ) in which the collimator lens ( 42 ) is positioned with respect to the reference optical axis ( 5 ) with high accuracy.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a technique for positioning an opticalelement and fixing the same.

2. Description of the Background Art

In an optical element module (i.e., a module comprising an opticalelement(s), such as a module comprising an optical fiber and an opticalcommunication device), conventionally, in order to position amicroscopic optical element with respect to a predetermined optical axisand fix the optical element (in other words, for alignment, to adjustthe position and orientation of the microscopic optical element), theoptical element is moved in one or two directions and positioned, beingin contact with a contact surface(s) of a holding member, and then fixedby filling its surrounding with solder or a bonding agent (e.g., abonding agent containing UV curing resin), or by laser fusion bondingwith emission of high-energy pulsed light such as YAG laser or glassfusion bonding with glass powder.

For example, since a semiconductor laser used in a light source or thelike has a large divergence angle of an emitted light beam (e.g.,several tens degrees), in general, the light beam is changed into aparallel ray by using combination of collimator lenses. Specifically, asshown in FIG. 1, a holding member 92 to which a semiconductor laser 91is fixed is provided with a contact surface 92 a and an adjustmentassisting member 94 on which a collimator lens 93 is fixed is insertedin the holding member 92, being in contact with the contact surface 92a. Then, the adjustment assisting member 94 is moved in a directionindicated by the arrow 95 of FIG. 1 to perform a collimating adjustmentfor adjusting the degree of parallelization of the light beam, and theadjustment assisting member 94 and the holding member 92 are fixed toeach other.

In a multichannel optical fiber connector which is used in applicationsusing optical fibers, such as optical fiber communications, (which isused, for example, in multichannel transmission to increase transmissioncapacity) and a light source unit such as a laser scan type image outputapparatus and the like, a plurality of optical fibers areone-dimensionally or two-dimensionally arranged with high accuracy. Inorder to arrange the optical fibers, grooves 96 each having a V-shapedsection are formed in such an arrangement as shown in FIG. 2 with adiamond cutter or the like in a holding member 97 formed of ceramics.Each optical fiber 98 is positioned, being in contact with side surfaces96 a of the groove 96, and then fixed.

FIG. 3 shows positioning and fixing of a bare chip 191 of semiconductorlaser (hereinafter, referred to as a “semiconductor laser”) and anoptical fiber 192. Also in this case, the optical fiber 192 ispositioned relatively to a holding member 193 on which a groove 193 ahaving a V-shaped section is formed, by bringing a tip portion of theoptical fiber 192 into contact with side surfaces of the groove 193 a.The semiconductor laser 191 supported by a collet (not shown) ispositioned with respect to the optical fiber 192, being in contact withan upper surface of the holding member 193, and fixed by a bonding agent(such as solder).

In a case of coupling (or splice) as shown in FIG. 4 where an opticalwaveguide element 194 and a plurality of optical fibers 192 arepositioned and fixed to each other, the optical waveguide element 194 ispositioned relatively to the holding member 195 and fixed thereto. On apositioning member 196 on which a plurality of grooves 196 a each havinga V-shaped section are formed and a positioning member 197 on which agroove 197 a also having the V-shaped section, a plurality of opticalfibers 192 are fixed with a bonding agent or the like, being in contactwith respective side surfaces of the grooves 196 a and 197 a, and thepositioning members 196 and 197 are fixed onto the holding member 195,to position the optical fibers 192 with respect to the optical waveguideelement 194.

There is relevant technique which is shown in the following document.

-   -   “Optical and Electro-optical Engineering Contact” (Japan        Optomechatronics Association, 1996/12/20, Vol. 34, No. 12        (1996), p.p. 619-627 and 636-640).    -   “OPTRONICS” (Optronics Co., Ltd., 1999/4/10, No. 4 (1999), p.p.        129-133 and 140-149).    -   “OPTRONICS” (Optronics Co., Ltd., 1999/7/10, No. 7 (1999), p.p.        149-155).

In the exemplary case of FIG. 1, since the collimator lens 93 can bemoved only in the direction indicated by the arrow 95 and the positionand orientation thereof with respect to other directions depend onprocessing accuracy or the like of the members, it is difficult toperform an adjustment even in a case where a fine adjustment is needed,such as, where an emission angle of the light beam from thesemiconductor laser 91 slightly deviates. If it is intended to increasethe degree of freedom in adjustment, the structure becomes complicatedand this causes a problem of increasing a manufacturing cost and thelike.

In the exemplary case of FIG. 2, though ceramics which is less affectedby temperature change or the like is generally used as the holdingmember 97, the ceramics is a costly material and needs a high machiningcost. Further, with this method, it is difficult to deal a complicatedarrangement.

In the optical element module of FIG. 3, though the optical fiber 192can be adjusted to a predetermined position only in the Z direction, theposition and orientation with respect to other directions depend on theshape of the groove 193 a. Though the semiconductor laser 191 can bepositioned with respect to the optical fiber 192 by moving it in the Xand Z directions, the position thereof in the Y direction can not bedetermined freely. As a result, while it is possible to ensure highrelative positioning accuracy of 1 to 2 μm in the X and Z directions,the relative positioning accuracy in the Y direction becomes worse(e.g., several μm) than that in the X and Z directions since it dependson the machining accuracy of the groove 193 a and the reproducibility inthickness of the bonding agent.

In the optical element module of FIG. 4, while it is possible to ensurethe positioning accuracy of about 0.2 μm with respect to the opticalwaveguide element 194 in the X and Z directions by applying a bondingagent or the like between the positioning members 196 and 197 and theholding member 195 and adjusting the bonding position, the positioningaccuracy in the Y direction is about 1 μm due to variations in machiningaccuracy of the grooves 196 a and 197 a and diameter of the opticalfibers 192, and the like.

SUMMARY OF THE INVENTION

It is an object of the present invention to simplify a structure of anoptical element module in which an optical element is positioned withhigh accuracy. It is another object of the present invention to positionand fix the optical element with high accuracy.

The present invention is intended for an optical element module.According to the present invention, the optical element module comprisesa base part to which a predetermined reference optical axis isrelatively fixed, an optical element positioned with respect to thereference optical axis, being out of contact with the base part, andsolder interposed between the optical element and the base part, forfixing the optical element onto the base part.

Since the optical element is positioned and fixed onto the base part outof contact therewith, a structure of the optical element module issimplified.

According to a preferred embodiment of the present invention, the basepart is a part which is fixed to another optical element whichdetermines the reference optical axis. Among the optical elementsrequiring high-accuracy positioning are a collimator lens, asemiconductor light emitting element, an optical waveguide element, anoptical fiber and the like.

The present invention is also intended for an apparatus for fixing anoptical element onto a base part. According to the present invention,the apparatus comprises a holding part for holding a base part to whicha bonding agent for fixing a first optical element is applied, asupporting part which supports the first optical element while movingthe same to the base part and is removed from the first optical elementafter fixing, a light receiving part for receiving a reference lightemitted from the first optical element or a second optical elementattached onto at the base part, a mechanism for moving or rotating thesupporting part relatively to the holding part, and a control part forpositioning the first optical element at a position with respect to thesecond optical element on the basis of an output from the lightreceiving part.

By using the output from the light receiving part, it is possible toposition and fix the optical element onto the base part with highaccuracy.

Preferably, the control part controls a position of the first opticalelement in the course of hardening of the bonding agent.

Still preferably, the apparatus further comprises a switching lens whichis movable to and fro on an optical path, between the light receivingpart and a front optical element that is one of the first and secondoptical elements which is closer to the light receiving part, and in theapparatus, the front optical element is a lens and the front opticalelement and a light receiving surface in the light receiving part areoptically conjugate to each other in a state where the switching lens isdisposed on the optical path. This allows positioning of the opticalelement on the basis of the state of light immediately after beingemitted from the front optical element.

According to one preferred embodiment of the present invention, a movingor rotating mechanism moves or rotates the supporting part relatively tothe holding part with respect to at least three axes. It is therebypossible to freely position the optical element.

As a bonding agent for fixing the optical element with high accuracy,preferably, glass powder or solder is used.

In this apparatus, positioning of the first optical element is notnecessarily performed with respect to the second optical element, butthere may be a case where the light receiving part receives a referencelight emitted from the optical element and positioning of the lightreceiving element is thereby performed.

The present invention is further intended for a method of fixing anoptical element onto a base part.

These and other objects, features, aspects and advantages of the presentinvention will become more apparent from the following detaileddescription of the present invention when taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross section illustrating a background-art optical elementmodule;

FIG. 2 is a perspective view illustrating another background-art opticalelement module;

FIG. 3 is a view showing manufacture of still another background-artoptical element module;

FIG. 4 is a perspective view showing yet another background-art opticalelement module;

FIG. 5 is a perspective view showing an optical element fixing apparatusin accordance with a first preferred embodiment;

FIG. 6 is a block diagram showing a constitution of the optical elementfixing apparatus;

FIGS. 7A to 7C are views showing basic structures of optical elementmodules;

FIG. 8 is a view showing an exemplary manufacture of the optical elementmodule;

FIG. 9 is a flowchart showing a process flow of manufacturing theoptical element module;

FIG. 10 is a graph showing a temperature profile of a holding part;

FIGS. 11A to 11D are views showing states of positioning of a collimatorlens;

FIG. 12 is a view showing manufacture of the optical element module;

FIG. 13 is a perspective view showing an optical head;

FIG. 14 is a perspective view showing another exemplary optical elementmodule;

FIG. 15 is a view showing manufacture of the optical element module;

FIG. 16 is a view showing another exemplary manufacture of an opticalelement module;

FIG. 17 is a view showing manufacture of the optical element module;

FIG. 18 is a view showing still another exemplary manufacture of anoptical element module;

FIG. 19 is a view showing manufacture of the optical element module;

FIG. 20 is a perspective view showing an optical element fixingapparatus in accordance with a second preferred embodiment; and

FIG. 21 is a perspective view showing an optical element fixingapparatus in accordance with a third preferred embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 5 is a perspective view showing an optical element fixing apparatus101 in accordance with the first preferred embodiment of the presentinvention. The optical element fixing apparatus 101 of FIG. 5 is anapparatus for positioning and fixing a collimator lens 42 (e.g., aSELFOC microlens (SELFOC: registered trademark) or an aspherical presslens having a diameter of about 1 mm) to a base part 22 to which asemiconductor laser 41 for emitting a light beam is fixed. With thisoptical element fixing apparatus 101, an optical element module(hereinafter, referred to as “semiconductor laser module”) 11 foremitting the light beam as a parallel ray is manufactured. The opticalelement fixing apparatus 101 comprises a holding part 121 for holdingthe base part 22, a supporting arm 61 for supporting the collimator lens42 and a control unit 105 constituted of a CPU for various computations,memories for storing various information and the like.

The holding part 121 is provided on a plate 120 extending in the Zdirection of FIG. 5. On an upper surface of the holding part 121, a basepart assisting member 122 used for positioning the base part 22protruding in the (+Y) direction and a collimator lens assisting member123 on which a groove having a V-shaped section is formed are provided.On the collimator lens assisting member 123, the collimator lens 42before assembling is disposed, being in contact with side surfaces ofthe groove. The holding part 121 is further provided with a holding partheater 124 for heating the holding part 121, a temperature sensor 125for sensing the surface temperature of the holding part 121 and probepins 126 (having an anode terminal and a cathode terminal) connected tothe semiconductor laser 41, and the holding part heater 124, thetemperature sensor 125 and the probe pin 126 are connected to thecontrol unit 105.

The supporting arm 61 is provided with an arm heater 161 connected tothe control unit 105, and the surface temperature of the supporting arm61 is controlled by the arm heater 161. The supporting arm 61 issupported by later-discussed moving mechanisms to be movable in the Ydirection and rotatable around rotation axes parallel to the X axis, theY axis and the Z axis (hereinafter, referred to as α axis, β axis and γaxis, respectively),

The optical element fixing apparatus 101 has an X-direction movingmechanism 131 for moving the holding part 121 in the X direction of FIG.5 and a Z-direction moving mechanism 134 for moving the holding part 121in the Z direction. The X-direction moving mechanism 131 provided on abase 111 has an X stage 133 on which an X-direction adjusting mechanism132 having a micrometer is fixed, and the X-direction adjustingmechanism 132 is controlled to move the X stage 133 in the X directionalong guide rails (not shown) provided between the base 111 and thestage 133. The Z-direction moving mechanism 134 has the sameconstitution and a Z-direction adjusting mechanism 135 having amicrometer is controlled to move a Z stage 136 fixed onto the plate 120in the Z direction. The X-direction moving mechanism 131 and theZ-direction moving mechanism 134 are connected to the control unit 105.

The optical element fixing apparatus 101 further has a Y-directionmoving mechanism 137 for moving the supporting arm 61 in the Ydirection, an a rotation mechanism 141 rotating around the α axis, a γrotation mechanism 144 rotating around the γ axis and a β rotationmechanism 147 rotating around the β axis. The Y-direction movingmechanism 137 is attached onto a plate 112 provided on the base 111 andhas a Y stage 139 on which a Y-direction adjusting mechanism 138 havinga micrometer is fixed. The Y-direction adjusting mechanism 138 iscontrolled to move the Y stage 139 in the Y direction.

A reduction gear motor 142 of the α rotation mechanism 141 is attachedonto the Y stage 139 and the reduction gear motor 142 is controlled torotate a a table 143 around the α axis. On the α table 143, an L-shapedmember 140 is fixed. The L-shaped member 140 has a surface 140 aprotruding in the X direction and having a normal parallel to the Zaxis, and the γ rotation mechanism 144 is attached onto the surface 140a. The γ rotation mechanism 144 has the same constitution as the αrotation mechanism 141, and a γ table 146 is rotated by a reduction gearmotor 145 around the γ axis. A β rotation mechanism 147 supporting thesupporting arm 61 rotatably around the β axis is provided on the γ table146, and the supporting arm 61 is rotated around the β axis by areduction gear motor 148 of the β rotation mechanism 147. TheY-direction moving mechanism 137, the rotation mechanisms 141, 144 and147 are connected to the control unit 105.

The optical element fixing apparatus 101 firther has an image pickuppart 7 (e.g., a CCD camera) receiving the light beam from thesemiconductor laser 41 connected to the probe pins 126, which isprovided on the plate 120, being opposed to the holding part 121. Theimage pickup part 7 has a sensing lens 171 and an image pickup device172, and the light beam from the semiconductor laser 41 are received bythe image pickup device 172 through the sensing lens 171. A switchinglens 173 is further provided on the plate 120, being movable to and froon an optical path of the light beam between the image pickup part 7 andthe collimator lens 42. In the state where the switching lens 173 isdisposed on the optical path, the collimator lens 42 and the imagepickup device 172 (exactly, a light receiving surface of the imagepickup device 172) are made optically conjugate to each other by theswitching lens 173 and the sensing lens 171. An auxiliary image pickuppart 174 having a microlens is provided over the image pickup part 7 andpicks up an image of the neighborhood of the collimator lens 42 on thebase part 22.

FIG. 6 is a block diagram showing a constitution of the optical elementfixing apparatus 101, and a control part 151, an image processing part152 and an arm moving control part 153 are contained in the control unit105 of FIG. 5. The image processing part 152 performs various processingon image data from the image pickup part 7 and outputs a signal to thecontrol part 151. The arm moving control part 153 controls the movingmechanisms 131, 134 and 137 and the rotation mechanisms 141, 144 and 147(hereinafter, referred to generally as an “arm moving mechanism 130”) onthe basis of the signal from the control part 151, and the supportingarm 61 thereby moves relatively to the holding part 121 along the threemotion axes (i.e., the X axis, the Y axis and the Z axis) which areorthogonal to one another and rotates relatively to the holding part 121around the three rotation axes (i.e., the α axis, the β axis and the γaxis) which are orthogonal to one another. In the optical element fixingapparatus 101, the control part 151 further controls the otherconstituent elements, to manufacture an optical element module.

Herein, discussion will be made on a basic structure of the opticalelement module manufactured by the optical element fixing apparatus 101.FIGS. 7A to 7C are views showing the basic structures of optical elementmodules. In an optical element module 1 a in accordance with a firstbasic structure shown in FIG. 7A, above a base part 2 on which apredetermined optical axis 5 (i.e., an axis used as a reference forpositioning of the optical element, and hereinafter, referred to as a“reference optical axis 5”) is relatively fixed, an optical element 4 isdisposed, which is positioned with respect to the reference optical axis5. Solder 3 is interposed between the base part 2 and the opticalelement 4, and the optical element 4 is fixed on the base part 2 out ofcontact therewith. When the optical element 4 is positioned, the opticalelement 4 is supported by a supporting part 6 (which corresponds to thesupporting arm 61), being movable along the three-axis directions (i.e.,the X axis direction, the Y axis direction and the Z axis direction ofFIG. 7A) which are orthogonal to one another and rotatable around therotation axes (i.e., the α axis, the β axis and the γ axis) which areparallel to the three axes, respectively. This allows the opticalelement 4 to be positioned with respect to the reference optical axis 5.

In an optical element module 1 b in accordance with a second basicstructure shown in FIG. 7B, with respect to the reference optical axis 5which is relatively fixed to one of two optical elements 4 (in otherwords, determined by one optical element 4), the other optical element 4is positioned and the two optical elements 4 are fixed out of contactwith each other with the solder 3 interposed therebetween. In an opticalelement module 1 c in accordance with a third basic structure shown inFIG. 7C, above the base part 2 on which the reference optical axis 5 isrelatively fixed, a plurality of optical elements 4 are disposed, whichare individually positioned with respect to the reference optical axis5, and the optical elements 4 are fixed onto the base part 2 out ofcontact therewith, with the solder 3 interposed therebetween. When theoptical element modules 1 a, 1 b and 1 c are manufactured, the opticalelements 4 are positioned by the supporting part 6 having flexibilitywith respect to the six axes.

In the second basic structure, the reference optical axis 5 isdetermined by one optical element 4, which serves as a reference forpositioning of the other optical element 4, and if part of the oneoptical element 4 is considered to correspond to the base part 2 in thefirst basic structure, the second basic structure can be regarded as anapplication of the first basic structure. In the third basic structure,if relatively to the base part 2 on which one optical element 4determining the reference optical axis 5 is fixed, the other opticalelement 4 is considered to be positioned, the third basic structure canbe also regarded as an application of the first basic structure.

FIG. 8 is a view showing an exemplary manufacture of the semiconductorlaser module 11 by the optical element fixing apparatus 101 (where onlypart of members on the holding part 121, the supporting arm 61 and theimage pickup part 7 are shown), and FIG. 9 is a flowchart showing aprocess flow of manufacturing the semiconductor laser module 11.Discussion will be made on a manufacturing process and a structure ofthe semiconductor laser module 11 according to the flow of FIG. 9,referring to FIGS. 5, 6 and 8.

The base part 22 is provided with a bonding part 221 protruding in the(+Y) direction of FIG. 8, and a groove 222 having a U-shaped section isformed on the bonding part 221. The semiconductor laser 41 for emittingthe light beam is fixed onto a plate-like submount 21 with solder 32interposed therebetween in advance, and the submount 21 is fixed ontothe base part 22 with solder 33 (preferably, whose melting point islower than that of the solder 32) interposed therebetween. At this time,the submount 21 and the semiconductor laser 41 are disposed so that asurface of the semiconductor laser 41 which emits the light beam shouldbe opposed to the bonding part 221. By providing the semiconductor laser41, the reference optical axis 5 corresponding to the light beam emittedfrom the semiconductor laser 41 is determined with respect to the basepart 22 (Step S11).

The base part 22 on which the semiconductor laser 41 is fixed isdisposed on the holding part 121 so that a side surface of the base part22 on the side of the bonding part 221 should come into contact with thebase part assisting member 122 (see FIG. 5) and positioned relatively tothe holding part 121. The reference surface on which the base part 22 ispositioned may be appropriately changed as necessary, and there may be acase, for example, where a member in contact with a side surface whichis orthogonal to the side surface of the base part 22 on the side of thebonding part 221 is provided on the holding part 121 and the base part22 is positioned by this member and an upper surface of the holding part121 (and the base part assisting member 122). In other words, in theoptical element fixing apparatus 101, the base part 22 has only to bedisposed on the holding part 121 with a certain surface as the referencesurface.

Subsequently, the collimator lens 42 on the collimator lens assistingmember 123 is supported by the supporting arm 61 with solder 60interposed therebetween (Step S112). Specifically, under control of thecontrol part 151, the supporting arm 61 is moved by the arm movingmechanism 130 to a position above the collimator lens 42 disposed on thecollimator lens assisting member 123 while being heated by the armheater 161, and the solder 60 is applied to a tip portion of thesupporting arm 61. The tip portion of the supporting arm 61 and thecollimator lens 42 come into contact with each other and heating by thearm heater 161 is stopped. Though the collimator lens 42 is formed ofglass, a metal such as gold is evaporated (metallized) on its outerperipheral surface in advance in order to fix the collimator lens 42 tothe tip portion of the supporting arm 61 with the solder 60 interposedtherebetween. This allows the supporting arm 61 to easily support thecollimator lens 42. Since the collimator lens 42 is disposed along thegroove of the collimator lens assisting member 123, the collimator lens42 can be supported by the supporting arm 61 at a predeterminedorientation.

Powdered solder 31 (such as ball solder and cream solder) is applied (orwas applied in advance) to the groove 222 of the bonding part 221. Asthe solder 31, one whose melting point is lower than those of thesolders 32, 33 and 60 (for example, 140 degrees) is used, and the basepart 22 is heated by the holding part heater 124 up to the melting pointof the solder 31 with the holding part 121 interposed therebetween.

FIG. 10 is a graph showing a relation between temperature of the holdingpart 121 which is sensed by the temperature sensor 125 and time (i.e., atemperature profile). In FIG. 10, time T1 indicates the time whenheating of the holding part heater 124 is started and the temperature ofthe holding part 121 at time T2 becomes a temperature A where the solder31 is melted. After the temperature of the holding part 121 rises to A,the temperature of the holding part 121 is kept at A (or slightly highertemperature than A) by the holding part heater 124. Melting of thesolder 31 is picked up by the auxiliary image pickup part 174 as animage and checked by the acquired image. When the solder 31 is melted,the collimator lens 42 is transferred to the groove 222 by thesupporting arm 61 (Step S13).

A semiconductor laser driving part (not shown) contained in the controlunit 105 is electrically connected to the semiconductor laser 41 throughthe probe pins 126 and controls the semiconductor laser 41 to emit thelight beam towards the collimator lens 42 (in other words, in the (−Z)direction of FIG. 8). The light beam is guided to the image pickup part7 positioned on the (−Z) side of the base part 22 through the collimatorlens 42. The image pickup part 7 acquires an image representing thestate of the light beam led out from the collimator lens 42 (Step S14)and outputs the image to the image processing part 152 (see FIG. 6). Theimage processing part 152 appropriately processes the acquired image andoutputs the processed image to the control part 151. The control part151 outputs a control signal on the basis of the processed image to thearm moving control part 153, by which the supporting arm 61 moves thecollimator lens 42 in the X axis, Y axis and Z axis directions androtates the collimator lens 42 around the α axis, the β axis and the γaxis to perform an adjustment of the position and orientation of thecollimator lens 42 (i.e., active alignment) with respect to thesemiconductor laser 41 (in other words, so that the light beam should goalong the reference optical axis 5) (Step S15).

FIGS. 11A to 11D are views showing states of positioning of thecollimator lens 42. FIG. 11A shows a state where the collimator lens 42is appropriately positioned. In FIG. 11A, the light beam from thecollimator lens 42 is changed into a parallel ray which are parallel tothe reference optical axis 5 (in other words, with high degree ofparallelization (collimating accuracy)), and the light beam form a smallspot on the image pickup device 172 through the sensing lens 171 (inother words, the size of a bright region in the acquired image issmall). Since the light beam is emitted to a predetermined position ofthe image pickup device 172, it is confirmed that the directivity of thelight beam is good.

In a state of FIG. 11B, as the collimating accuracy of the light beam isnot sufficiently adjusted, a large spot is formed on the image pickupdevice 172 and the bright region in the acquired image is blurred. In astate of FIG. 11 C, the position or orientation of the collimator lens42 is not appropriate and the direction of the light beam deviates fromthe reference optical axis 5, and the light beam can not be emitted tothe predetermined position on the image pickup device 172.

In a case where the semiconductor laser module 11 is used in a lightsource of an image recording apparatus and the like, since the lightbeam just emitted from the collimator lens 42 is used (i.e., the shapeof the light beam at the collimator lens 42 is projected on the object),a fine adjustment on the position and orientation of the collimator lens42 is performed with the switching lens 173 disposed on the optical pathof the light beam, as shown in FIG. 11D, besides the above-discussedadjustment on collimating accuracy and directivity of the light beam.Specifically, an image representing a state of the light beamimmediately after being led out from the collimator lens 42 is acquiredand the collimator lens 42 is positioned on the basis of the image (inother words, the sectional shape of the light beam immediately afterbeing led out). Steps S14 and S15 are repeated as necessary.

FIG. 12 is a view showing the semiconductor laser module 11 in course ofmanufacture as viewed from the (−Z) side towards the (+Z) direction. Asshown in FIG. 12, the collimator lens 42 which is positioned with highaccuracy (e.g., with an accuracy of 0.1 to 0.2 μm with respect to thereference optical axis 5) is out of contact with the base part 22 andthe solder 31 is entirely interposed between the collimator lens 42 andthe base part 22. This state can be confirmed with the image acquired bythe auxiliary image pickup part 174. After the collimator lens 42 ispositioned, the heating by the holding part heater 124 is subsequentlystopped (at time T3 of FIG. 10) and the solder 31 is naturally cooledand starts to be hardened (Step S16).

When the temperatures of the members are lowered, though the relativeposition of the collimator lens 42 with respect to the reference opticalaxis 5 is moved by shrinkage of these members, also in course ofhardening of the solder 31, the image pickup part 7 acquires the imageof the light beam led out from the collimator lens 42 (Step S17) andchecks the position of the collimator lens 42 (Step S18), and thecontrol part 151 positions the collimator lens 42 following the relativemove of the reference optical axis 5 (Step S19). Steps S17 to S19 arerepeated until the hardening of the solder 31 is completed (Step S20),and this keeps the relative position and orientation of the collimatorlens 42 with respect to the reference optical axis 5 (in other words,the collimator lens 42 is positioned so that the image acquired by theimage pickup part 7 should almost keep the state immediately before thehardening of the solder 31 starts).

After the solder 31 is hardened (at time T4 of FIG. 10), the imageacquired by the image pickup part 7 keeps a constant state and thetemperature sensor 125 confirms that the temperature of the holding part121 is not higher than a predetermined temperature (the temperature B ofFIG. 10 (e.g., a temperature lower than the temperature A by severaltens degrees)). After that, the supporting arm 61 is heated by the armheater 161, the solder 60 is melted and the supporting arm 61 is removedfrom the collimator lens 42 (Step S21), to complete the semiconductorlaser module 11.

Thus, in the optical element fixing apparatus 101, the collimator lens42 can be positioned with respect to the reference optical axis 5 withhigh accuracy and fixed with solder 31 onto the base part 22 which isfixed to the semiconductor laser 41, being out of contact with the basepart 22. As a result, the optical element fixing apparatus 101 canmanufacture the semiconductor laser module 11 which emits an appropriatelight beam with high directivity and collimating accuracy, and thestructure of the semiconductor laser module 11 can be simplified (andsize-downed).

In the optical element fixing apparatus 101, since the orientation ofthe collimator lens 42 is adjusted by the collimator lens assistingmember 123 in advance, the supporting arm 61 moves with respect to atleast three axes (herein, the X axis, the Y axis and the Z axis)relatively to the holding part 121 to thereby temporarily position thecollimator lens 42 with high accuracy. Even if the orientation of thecollimator lens 42 changes when the collimator lens 42 is supported bythe supporting arm 61, the supporting arm 61 relatively moves along thethree motion axes (i.e., the X axis, the Y axis and the Z axis) andrelatively rotates around the three rotation axes (i.e., the α axis, theβ axis and the γ axis) to thereby position the collimator lens 42 ontothe base part 22 out of contact therewith, with high accuracy.

The semiconductor laser module 11 corresponds to the optical elementmodule 1 a in accordance with the first basic structure among the threebasic structures shown in FIGS. 7A to 7C. Specifically, the collimatorlens 42 is positioned with respect to the reference optical axis 5 fixedonto the base part 22 by fixing the semiconductor laser 41. Thesemiconductor laser 41 (or the submount 21 to which the semiconductorlaser 41 is fixed) may be positioned with respect to a reference opticalaxis which is assumed relatively to the base part 22 and fixed onto thebase part 22 out of contact therewith with the solder interposedtherebetween, and in this case, the semiconductor laser modulecorresponds to the optical element module Ic in accordance with thethird basic structure of FIG. 7C.

FIG. 13 is a perspective view showing an optical head 8 using theabove-described semiconductor laser modules 11. The optical head 8 has amultichannel light source unit 81, and the light beams from the lightsource unit 81 are emitted to an exposure region where a photosensitivematerial or the like are positioned, through a group of lenses 82 whichare constituents of a both-side telecentric optical system. The lightsource unit 81 has a module supporting part 811 for supporting thesemiconductor laser modules 11, a semiconductor laser driving controlpart 812 for controlling drive of the semiconductor laser modules 11 anda temperature control part 813 for controlling the temperature of thesemiconductor laser modules 11, and the semiconductor laser modules 11are inserted into a plurality of holes formed on the module supportingpart 811 in a two-dimensional arrangement.

In this case, since the semiconductor laser module 11 is adjusted with aside surface of the base part 22 on the side of the bonding part 221 asa reference surface (in other words, the collimator lens 42 ispositioned), the side surface comes into contact with a surface of themodule supporting part 811 to thereby achieve an accurate positioning inthe optical head 8.

By using the semiconductor laser modules 11, a small-sized optical head8 capable of emitting multichannel light beams appropriately (forexample, with a constant directivity) is achieved, and it is therebypossible to perform size-reduction of an image recording apparatus (suchas raster scan type image recording apparatus) and high-accuracydrawing.

FIG. 14 is a perspective view showing another exemplary optical elementmodule 12 manufactured by the optical element fixing apparatus 101. Theoptical element module 12 of FIG. 14 (such as a Mach-Zehnder typemodulator) has an optical fiber 43, an optical waveguide element 44formed of a dielectric material such as Lithium Niobate (LiNbO₃) (LN) ora semiconductor material such as gallium arsenide (GaAs), a microlensarray 45 in which a plurality of lenses 451 are arranged and a base part23, and a light beam is guided from the optical fiber 43 connected to anexternal light source (e.g., a semiconductor laser) to the opticalwaveguide element 44. The light beam is branched in the opticalwaveguide element 44 and the branched light beams are guided out to thelenses 451 included in the microlens array 45. Thus, modulated lightbeams are guided to a predetermined position.

FIG. 15 is a view showing the optical element module 12 on the opticalelement fixing apparatus 101 as viewed from the (+X) side towards the(−X) direction, and only shows the optical element module 12 and thesupporting arm 61 (or a supporting arm 62). The tip portion of thesupporting arm 62 is a gripper 621. In manufacturing the optical elementmodule 12, the supporting arm 61 and the supporting arm 62 are changedproperly in accordance with the process in the optical element fixingapparatus 101, with the base part 23 held by the holding part 121, butFIG. 15 shows both supporting arms. In the optical element module 12,after the optical fiber 43 is positioned relatively to the opticalwaveguide element 44, the microlens array 45 is positioned. Detaileddiscussion will be made below on a manufacturing process and a structureof the optical element module 12 according to the flow of themanufacturing process in FIG. 9.

The optical waveguide element 44 has a plurality of optical waveguideoutlets 442 for one optical waveguide inlet 441 and is fixed on the basepart 23. This determines a reference optical axis 5 a corresponding tothe orientation of the optical waveguide inlet 441 of the opticalwaveguide element 44 with respect to the base part 23 (Step S11).Subsequently, the optical fiber 43 whose tip portion is metallized (orprovided with a metal sleeve) is supported by the supporting arm 61 atanother portion (for example, on an assisting member for the opticalfiber 43) on the holding part 121 with the solder 60 interposedtherebetween (Step S12). Solder 31 a is applied to the base part 23 onthe side of the optical waveguide inlet 441 of the optical waveguideelement 44 and the base part 23 is heated up to the melting point of thesolder 31 a (in other words, the holding part 121 is heated) to melt thesolder 31 a. Then, the optical fiber 43 is moved to the opticalwaveguide inlet 441 by the supporting arm 61 (Step S13).

In course of manufacture, light from a light source which is separatelyprovided can be led to the optical fiber 43, and the light beam led tothe optical fiber 43 is guided through the optical waveguide inlet 441to the inside of the optical waveguide element 44 and the branchedlights are guided out from a plurality of optical waveguide outlets 442,respectively. The lights guided out go through a dedicated lens systemwhich is separately provided and are received by the image pickup part 7(see FIG. 5), where an image of the lights is acquired (Step S14). Thesupporting arm 61 uses the arm moving mechanism 130 to move the opticalfiber 43 in the X axis, Y axis and Z axis directions and rotate theoptical fiber 43 around the α axis, the β axis and the γ axis on thebasis of the brightness and distribution of lights represented by theacquired image, to position the tip portion of the optical fiber 43 sothat the image representing the state of lights should be apredetermined state (in other words, the tip portion of the opticalfiber 43 should go along the reference optical axis 5 a) (Step S15). Atthis time, the solder 31 a is interposed between the optical fiber 43and the base part 23.

Subsequently, hardening of the solder 31 a is started by stopping theheating of the base part 23 (Step S16) and positioning of the opticalfiber 43 is repeated following the relative move of the referenceoptical axis 5 a caused by cooling (Steps S17 to S19). When thehardening of the solder 31 a is completed (Step S20), the supporting arm61 is heated by the arm heater 161 to meld the solder 60 and removedfrom the optical fiber 43 (Step S21).

When the optical fiber 43 is fixed onto the base part 23, subsequently,the microlens array 45 is gripped with the gripper 621 of the supportingarm 62 at another portion on the holding part 121 (Step S12). Since aplurality of reference optical axes 5 b serving as the reference forpositioning of the microlens array 45 correspond to the orientations ofa plurality of optical waveguide outlets 442 of the optical waveguideelement 44, a plurality of reference optical axes 5 b are determined atthe time when the optical waveguide element 44 is fixed onto the basepart 23 (which corresponds to Step S11).

Then, the solder 31 b is applied to a side surface 231 of the base part23 on the side of the optical waveguide outlets 442 (i.e., the (−Z)side) while the base part 23 is heated up to the melting point of thesolder 31 b, and the microlens array 45 is moved to the side surface 231by the supporting arm 62 (Step S13). The interval of the lenses 451 inthe microlens array 45 is equal to the interval of the optical waveguideoutlets 442, and the microlens array 45 is held at such a position asthe lenses 451 correspond to the optical waveguide outlets 442,respectively. A surface of the microlens array 45 which faces the basepart 23 is metallized and solder whose melting point is lower than thatof the solder 31 a is used as the solder 31 b.

A plurality of lights guided out from the optical waveguide outlets 442of the optical waveguide element 44 towards the microlens array 45 areled to the image pickup part 7 through the lenses 451 (see FIG. 5) andimages corresponding to the lights are acquired (Step S14). With controlof the control part 151, the supporting arm 62 moves the microlens array45 in the three directions orthogonal to one another and rotates themicrolens array 45 around the three axes orthogonal to one another onthe basis of the acquired images, and the microlens array 45 ispositioned so that a plurality of lights guided out should be in anappropriate state along the reference optical axes 5 b, respectively(Step S15). At this time, the solder 31 b is interposed between themicrolens array 45 and the base part 23. Then, the hardening of thesolder 31 b starts (Step S16) and the microlens array 45 is positionedfollowing the relative move of the reference optical axes 5 b (Steps S17to S19). When the hardening of the solder 31 b is completed (Step S20),the microlens array 45 is released from the gripping by the supportingarm 62 (Step S21).

Thus, in the optical element fixing apparatus 101, the optical fiber 43and the microlens array 45 are fixed onto the base part 23 out ofcontact therewith, with the solder 31 a and 31 b interposedtherebetween, while being positioned with respect to the referenceoptical axes 5 a and 5 b which are determined by the optical waveguideelement 44, respectively, with high accuracy. As a result, with theoptical element fixing apparatus 101, the optical element module 12 inwhich light is efficiently guided and branched lights are emitted in anappropriate direction can be easily manufactured and the structure ofthe optical element module 12 is simplified. The optical element module12 corresponds to the optical element module 1 a (FIG. 7A) in accordancewith the first basic structure in terms of the relation between the basepart 23 and the optical fiber 43 and corresponds to the optical elementmodule 1 b (FIG. 7B) in accordance with the second basic structure interms of the relation between the optical waveguide element 44 and themicrolens array 45 if the base part 23, the optical fiber 43 and theoptical waveguide element 44 are regarded as a unit.

FIG. 16 is a view showing still another exemplary optical element module13 manufactured by the optical element fixing apparatus 101. In theoptical element module 13 of FIG. 16, a plurality of semiconductorlasers 41 are fixed at positions corresponding to lenses 461 of amicrolens array 46, respectively, to form a multichannel light sourceunit. In manufacturing the optical element module 13 of FIG. 16, asupporting arm whose tip portion is a gripper facing towards the (−Z)direction is used as the supporting arm 62 and the microlens array 46 isheld by the holding part 121 at an upright posture.

FIG. 17 is a longitudinal section of the optical element module 13 andshows only part of the optical element module 13. Discussion will bemade below on a manufacturing process and a structure of the opticalelement module 13 according to the flow of FIG. 9.

In the optical element module 13, a plurality of reference optical axes5 serving as the reference for the manufacture correspond to respectiveaxes of the lenses 461 in the microlens array 46 (in other words, StepS11 of FIG. 9 is not needed). The semiconductor laser 41 is fixed ontothe submount 21 and the submount 21 is fixed onto an auxiliary plate 24in advance. Subsequently, the auxiliary plate 24 is gripped by thesupporting arm 62 which is movable in the X axis, Y axis and Z axisdirections and rotatable around the α axis, the β axis and the γ axis(Step S12). One surface 462 of the microlens array 46 is metallized andthe semiconductor laser 41, together with the auxiliary plate 24, ismoved to a position corresponding to one of the lenses 461 by thesupporting arm 62 (Step S13).

The solder 31 is applied between the auxiliary plate 24 and the mainsurface 462 while the auxiliary plate 24 is heated by the arm heater 161with the supporting arm 62 interposed therebetween up to the meltingpoint of the solder 31. This makes a state shown in FIG. 17 where thesolder 31 is interposed between the auxiliary plate 24 and the microlensarray 46.

Like the semiconductor laser module 11, the semiconductor laser 41 iselectrically connected to the semiconductor laser driving part and thesemiconductor laser driving part controls the semiconductor laser 41 toemit a light beam. The light beam is led to the image pickup part 7 (seeFIG. 5), where an image corresponding to the state of the light beam isacquired (Step S14).

With control of the control part 151, the supporting arm 62 moves androtates the semiconductor laser 41 on the basis of the acquired image toposition the semiconductor laser 41 with respect to the referenceoptical axis 5 (Step S15). At this time, the microlens array 46 and theauxiliary plate 24 are out of contact with each other and by stoppingthe heating of the auxiliary plate 24, hardening of the solder 31 starts(Step S16) and positioning of the semiconductor laser 41 is repeatedfollowing the relative move of the reference optical axis 5 (Steps S17to S19). When the hardening of the solder 31 is completed (Step S20),the auxiliary plate 24 is released from the gripping by the supportingarm 62 (Step S21).

Steps S12 to S21 are repeated for a plurality of reference optical axis5 and a plurality of semiconductor lasers 41 are fixed onto themicrolens array 46.

Thus, in the optical element fixing apparatus 101, a plurality ofsemiconductor laser 41 are positioned with high accuracy with respect toa plurality of reference optical axes 5, respectively, which aredetermined by a plurality of lenses 461 in the microlens array 46 whilebeing fixed onto the microlens array 46 out of contact therewith, withthe solder 31 interposed therebetween. This makes it possible to easilymanufacture the optical element module 13 which is a multichannel lightsource unit in the optical element fixing apparatus 101, and in theoptical element module 13, it is possible to determine the direction ofemitting light beams with high accuracy and simplify its structure. Theoptical element module 13, in which the microlens array 46 determines aplurality of reference optical axes 5 and serves as a base forsupporting the semiconductor lasers 41, corresponds to the opticalelement module lb of FIG. 7B in accordance with the second basicstructure in terms of the relation between each lens of the microlensarray 46 and the semiconductor laser 41.

FIG. 18 is a view showing manufacture of yet another exemplary opticalelement module 14 in the optical element fixing apparatus 101. Theoptical element module 14 has a structure in which a plurality ofoptical fibers 43 connected to a semiconductor lasers for opticalcommunications and the like are arranged on the base part 23 with highaccuracy. Hereinafter, the optical element module 14 is referred to as afiber array 14, and discussion will be made on the flow of manufacturingthe fiber array 14 according to FIG. 9 and the characteristic featuresin structure of the fiber array 14, referring to FIG. 18.

First, the base part 23 is opposed to the image pickup part 7 (in otherwords, disposed on the holding part 121), and a plurality of referenceoptical axes 5 which are assumed relatively to the base part 23 aredetermined (Step S11). Subsequently, the optical fiber 43 whose tipportion is metallized (or provided with a metal sleeve at its tipportion) is supported by the supporting arm 61 with the solder 60interposed therebetween (Step S12). The supporting arm 61 is movable inthe X axis, Y axis and Z axis directions and rotatable around the αaxis, the β axis and the γ axis and moves the optical fiber 43 to theneighborhood of a position corresponding to one of the reference opticalaxes 5 over the base part 23 (Step S13).

FIG. 19 is a view showing the fiber array 14 in course of manufacture asviewed from the (−Z) side towards the (+Z) direction. As shown in FIG.19, the solder 31 is applied to the base part 23 and the base part 23 isheated up to the melting point of the solder 31 (in other words, theholding part heater 124 heats the holding part 121) to melt the solder31, to make a state where the solder 31 is interposed between theoptical fiber 43 and the base part 23. At this time, a light beam isemitted from a core of the optical fiber 43 and the supporting arm 61moves on the basis of an image acquired by the image pickup part 7, toposition the optical fiber 43 with respect to the base part 23(specifically, so that the central axis of the optical fiber 43 shouldbe the reference optical axis 5) (Steps S14 and S15).

At this time, like the semiconductor laser module 11, by disposing theswitching lens 173 on the optical path, the position of the core of theoptical fiber 43 is confirmed and the optical fiber 43 is arrangedcorrespondingly to the reference optical axis 5. Then, the directivityof the light beam is confirmed by switching from the switching lens 173to another lens separately provided. Subsequently, the heating of thebase part 22 is stopped to start the hardening of the solder 31 (StepS16). While the image pickup part 7 checks an image of the light beam,positioning of the optical fiber 43 is repeated following the relativemove of the reference optical axis 5 (Steps S17 to S19).

When the hardening of the solder 31 a is completed (Step S20), thesupporting arm 61 is heated and removed from the optical fiber 43 (StepS21). By repeating Steps S12 to S21, the next optical fiber 43 ispositioned with respect to the next reference optical axis 5. Thus, aplurality of optical fibers 43 on the base part 23 are arranged withhigh accuracy. Since it is known from experiences that the solder 31which is once melted and hardened is melted again only when heated up toa temperature higher than the temperature at which the solder 31 ismelted immediately before, by controlling the temperature for heatingthe base part 23, it is possible to fix a plurality of optical fibers 43onto the base part 23.

In Step S18 discussed above, the move of the reference optical axis 5may be sensed on the basis of the light from the optical fiber 43 whichis already fixed or may be sensed by a sensor which is separatelyprovided.

Thus, in the optical element fixing apparatus 101, a plurality ofoptical fibers 43 can be positioned with high accuracy with respect to aplurality of reference optical axes 5 which are fixed relatively to thebase part 23 while being fixed onto the base part 23 out of contacttherewith, with the solder 31 interposed therebetween. This makes itpossible to simplify the structure of the fiber array 14 which can emita plurality of light beams with excellent directivity (in other words, aplurality of light beams whose emission angles are appropriatelycontrolled) and it is thereby possible to reduce the manufacturing cost.The structure of each optical fiber 43 and the base part 23 correspondsto the optical element module 1 a in accordance with the first basicstructure.

In the optical element fixing apparatus 101, glass powder may be used,instead of the solder 31, as a bonding agent for fixing the opticalelement, and in this case, the optical element (such as the collimatorlens 42) positioned with respect to the reference optical axis 5 isfixed onto the base part out of contact therewith, with the glass powderinterposed therebetween. The optical element fixing apparatus 101 canthereby manufacture the optical element module in which the opticalelement is fixed with the glass powder while being positioned with highaccuracy.

FIG. 20 is a perspective view showing an optical element fixingapparatus 101 a in accordance with the second preferred embodiment. Inthe optical element fixing apparatus 101 a of FIG. 20, a cooling part127 having an air nozzle 127 b connected to an air supply part 127 a isprovided and the cooling part 127 applies air (or nitrogen gas) towardsthe holding part 121. Other constituent elements in the optical elementfixing apparatus 101 a are the same as those in the optical elementfixing apparatus 101 in accordance with first preferred embodiment andrepresented by the same reference signs.

The optical element fixing apparatus 101 a of FIG. 20 is different fromthe optical element fixing apparatus 101 of FIG. 5 in method ofhardening the solder 31. Specifically, when the solder 31 is hardened inStep S16 of FIG. 9, the cooling part 127 applies air towards the holdingpart 121. In other words, in hardening the solder 31, the heating by theholding part heater 124 is stopped while the cooling part 127 performsforced cooling. It is thereby possible to harden the solder 31 in ashorter time in the optical element fixing apparatus 101 a. The methodof positioning the optical element (such as the collimator lens 42)following the relative move of the reference optical axis 5 in Steps S17to S20 is the same as that in the first preferred embodiment.

As another example of hardening the solder 31 in the optical elementfixing apparatus 101 a, there may be a case where the holding part 121is always heated by the holding part heater 124 and the cooling part 127applies air one after another. In the case of the semiconductor lasermodule 11, for example, first, the base part 22 on which thesemiconductor laser 41 is fixed is. disposed on the holding part 121whose temperature is kept at the melting temperature of the solder 31 bythe holding part heater 124 and then the solder 31 is melted (in otherwords, Step S13 is partly performed). The semiconductor laser 41 iselectrically connected through the probe pin 126 and the collimator lens42 is supported (may be supported in advance) by the supporting arm 61which is movable in the X axis, Y axis and Z axis directions androtatable around the α axis, the β axis and the γ axis (Step S12) andmoved to the groove 222 having the melted solder 31 (see FIG. 8) (StepS13). Then, like in the first preferred embodiment, the image pickuppart 7 acquires an image and the collimator lens 42 is quicklypositioned on the basis of the image (Steps S14 and S15).

Subsequently, the cooling part 127 applies air to the holding part 121which is being heated. At this time, the cooling part 127 cools only theneighborhood of the upper surface of the holding part 121 which includesthe base part 22, to lower the temperature thereof. The positioning ofthe collimator lens 42 is repeated following the relative move of thereference optical axis 5 caused by the temperature fall and then thehardening of the solder 31 is completed, to fix the collimator lens 42(Steps S16 to S20). The supporting arm 61 is removed from the collimatorlens 42 while being heated (Step S21) and the semiconductor laser module11 whose temperature is kept at the hardening temperature of the solder31 or lower is removed from the holding part 121. The application of airfrom the cooling part 127 is stopped and the temperature in theneighborhood of the upper surface of the holding part 121 is quicklyheated up to the melting temperature of the solder 31. Thus, in themethod of manufacturing the optical element module in accordance withanother example of the optical element fixing apparatus 101 a, since thetemperature profile (i.e., temperature change with time) of the basepart 22 is made equal to that in the first preferred embodiment whilethe holding part 121 is always heated, it is possible to appropriatelymanufacture the optical element module (such as the optical elementmodules 11 to 14).

Thus, in the optical element fixing apparatus 101 a of the secondpreferred embodiment, the holding part heater 124 and the cooling part127 control the temperature of the holding part 121. This allows quickmelting or hardening of the solder 31 in the optical element fixingapparatus 101 a and it is thereby possible to appropriately manufacturethe optical element module in which the optical element is positionedwith high accuracy.

FIG. 21 is a perspective view showing an optical element fixingapparatus 101b in accordance with the third preferred embodiment. Theoptical element fixing apparatus 101 b is different from the opticalelement fixing apparatus 101 of FIG. 5 in that the holding part heater124 and the temperature sensor 125 are not provided and instead a lightemitting part 128 is provided. The light emitting part 128 has anoptical fiber 128 b connected to a light source 128 a and emits light(e.g., a ultraviolet ray) towards the optical element module on theholding part 121. Other constituent elements in the optical elementfixing apparatus 101 b are the same as those in the optical elementfixing apparatus 101 in accordance with first preferred embodiment andrepresented by the same reference signs.

In the optical element fixing apparatus 101 b, a bonding agentcontaining an UV curing resin as an agent for bonding (i.e., fixing) theoptical element. Discussion will be made below on an exemplary case ofmanufacturing the semiconductor laser module 11, referring to FIG. 8(herein, the solder 31 of FIG. 8 is referred to as a bonding agent).Like in the first preferred embodiment, when the collimator lens 42supported by the supporting arm 61 which can move relatively to theholding part 121 along the three motion axes orthogonal to one anotherand rotate relatively to the holding part 121 around the three rotationaxes orthogonal to one another is moved to the groove 222 of the basepart 22 and positioned with respect to the reference optical axis 5 onthe basis of an output from the image pickup part 7 (Steps S11 to S15),the bonding agent (which corresponds to the reference numero 31 in FIG.8) is applied to the groove 222 and a ultraviolet ray is emitted fromthe light emitting part 128 towards the neighborhood of the groove 222.This starts hardening the bonding agent (Step S16), and positioning ofthe collimator lens 42 is repeated following the relative move of thereference optical axis 5 caused by shrinkage of the bonding agent whilethe relative move of the reference optical axis 5 is checked with animage acquired by the image pickup part 7 until the hardening of thebonding agent is completed (e.g., for several tens seconds) (Steps S17to S19).

When it is confirmed that the relative move of the reference opticalaxis 5 is stopped (in other words, it is confirmed that the hardening ofthe bonding agent is completed) (Step S20), the supporting arm 61 isheated to be removed from the collimator lens 42 and the semiconductorlaser module 11 is removed from the holding part 121. By this method,other optical element modules (such as the optical element modules 12 to14) may be manufactured in the optical element fixing apparatus 101 b.

Thus, in the optical element fixing apparatus 101 b of the thirdpreferred embodiment, since the light emitting part 128 is provided, itis possible to appropriately manufacture the optical element module inwhich the optical element is positioned with high accuracy while thebonding agent between the optical element and the base part is hardened.The resin component contained in the bonding agent is not limited to theUV curing resin but may be, for example, a thermosetting resin. In sucha case, the bonding agent may be hardened by the holding part heater 124like in the first preferred embodiment.

Though the preferred embodiments of the present invention have beendiscussed above, the present invention is not limited to theabove-discussed preferred embodiments, but allows various variations.

The supporting arm is not limited to those of the above-discussedpreferred embodiments but may be a collet which supports the opticalelement by vacuum adsorption. In a case where the collet is used, theoptical element gets supported or removed by ON/OFF of the vacuum. Inthe supporting arm which supports the optical element with solderinterposed therebetween, a bonding agent may be used instead of thesolder, and in such a case, the supporting arm and the optical elementmay be removed by rotation of the supporting arm.

In the optical element fixing apparatus, a bonding agent supply part forsupplying the bonding agent (including solder) may be provided to supplythe bonding agent to the base part on the basis of control of thecontrol part 151.

The light emitted through the optical element supported by thesupporting arm 61 or the optical element fixed onto the base part maynot be necessarily received by the image pickup part 7. In a case, forexample, where the optical element is positioned on the basis of onlythe directivity of the light, the light may be received by a PSD elementor the like which senses the position of the received light.

There may be case where a light source for emitting a light beam isprovided in the optical element fixing apparatus and the optical elementis positioned with the light beam as a reference optical axis.

In the optical element fixing apparatus, the optical element may bepositioned so that light guided out from the optical element should bein a desired state (for example, in a state after being subjected tocollimating adjustment) as well as positioned with respect to thereference optical axis in any optical element module. Specifically, in acase where the optical element module is constituted of a plurality ofoptical elements to be fixed and the optical element near the imagepickup part 7 (i.e., a front optical element in a traveling direction oflight) is a lens, the front optical element and the image pickup device172 of the image pickup part 7 are optically conjugate to each other ina state where the switching lens is disposed between the front opticalelement and the image pickup part 7, and any one of the optical elementsmay be positioned.

The optical element included in the optical element module is notlimited to a collimator lens, a lens included in a microlens array, anoptical fiber, a semiconductor laser or an optical waveguide element butother optical elements (e.g., a microscopic optical element requiringpositioning accuracy of several tens nm to several μm) may be adopted.The optical element fixing apparatus can position even the microscopicoptical element with high accuracy. The optical element which determinesthe reference optical axis 5 may be an optical element other than thesemiconductor laser, the optical waveguide element or the lens includedin the microlens array, and for example, as an optical element foremitting light, a semiconductor light emitting element, such as a lightemitting diode, which is different in type from the semiconductor laser,may be adopted.

In the optical element module having a plurality of optical elements tobe positioned, the manner in which the optical elements are arranged isnot limited to those of the preferred embodiments. Since the positionsand orientations of the optical elements can be freely determined (inother words, adjustment can be made with high degree of freedom) in theoptical element fixing apparatus, high-accuracy optical axis adjustmentcan be made while the optical elements are arranged in a complicatemanner.

While the invention has been shown and described in detail, theforegoing description is in all aspects illustrative and notrestrictive. It is therefore understood that numerous modifications andvariations can be devised without departing from the scope of theinvention.

1-11. (canceled)
 12. An apparatus for fixing an optical element onto abase part, comprising: a holding part for holding a base part to which abonding agent for fixing a first optical element is applied; asupporting part which supports said first optical element while movingthe same to said base part and is removed from said first opticalelement after fixing; a light receiving part for receiving a referencelight emitted from said first optical element or a second opticalelement attached onto said base part; a mechanism for moving or rotatingsaid supporting part relatively to said holding part; and a control partfor positioning said first optical element at a position with respect tosaid second optical element on the basis of an output from said lightreceiving part.
 13. The apparatus according to claim 12, wherein saidcontrol part controls a position of said first optical element in courseof hardening of said bonding agent.
 14. The apparatus according to claim12, wherein said first optical element is a collimator lens.
 15. Theapparatus according to claim 14, wherein said second optical element isa semiconductor light emitting element for emitting light towards saidcollimator lens.
 16. The apparatus according to claim 12, wherein saidfirst optical element is a microlens array.
 17. The apparatus accordingto claim 16, wherein said second optical element is an optical waveguideelement for emitting lights towards said microlens array.
 18. Theapparatus according to claim 16, wherein said second optical element isa semiconductor light emitting element for emitting a light towards saidmicrolens array.
 19. The apparatus according to claim 12, wherein saidfirst optical element is an optical fiber.
 20. The apparatus accordingto claim 12, further comprising a switching lens which is movable to andfro on an optical path, between said light receiving part and a frontoptical element that is one of said first and second optical elementswhich is closer to said light receiving part, wherein said front opticalelement is a lens and said front optical element and a light receivingsurface in said light receiving part are optically conjugate to eachother in a state where said switching lens is disposed on said opticalpath.
 21. An apparatus for fixing an optical element onto a base part,comprising: a holding part for holding a base part to which a bondingagent for bonding an optical element is applied; a supporting part whichsupports said optical element while moving the same to said base partand is removed from said optical element after fixing; and a movingmechanism for moving or rotating said supporting part relatively to saidholding part with respect to at least three axes.
 22. The apparatusaccording to claim 21, wherein said moving mechanism moves saidsupporting part relatively to said holding part along three motion axesand rotates said supporting part relatively to said holding part aroundthree rotation axes.
 23. The apparatus according to claim 21, whereinsaid optical element is one selected out of a group consisting of asemiconductor light emitting element, a collimator lens, a microlensarray and an optical fiber.
 24. The apparatus according to claim 21,further comprising a temperature control part for controllingtemperature of said supporting part, wherein said supporting partsupports said optical element with solder interposed therebetween. 25.The apparatus according to claim 21, wherein said bonding agent is abonding agent containing resin component, and said apparatus furthercomprising a mechanism for hardening said bonding agent on said basepart.
 26. The apparatus according to claim 21, wherein said bondingagent is glass powder or solder, and said apparatus further comprisinganother temperature control part for controlling temperature of saidholding part.
 27. An apparatus for fixing an optical element onto a basepart, comprising: a holding part for holding a base part to which abonding agent for fixing an optical element is applied; a supportingpart which supports said optical element while moving the same to saidbase part and is removed from said optical element after fixing; a lightreceiving part for receiving a reference light emitted from said opticalelement; a mechanism for moving or rotating said supporting partrelatively to said holding part; and a control part for positioning saidoptical element at a position with respect to said base part on thebasis of an output from said light receiving part. 28-30. (canceled)